US4752937A - Gas laser and production process therefor - Google Patents

Gas laser and production process therefor Download PDF

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Publication number
US4752937A
US4752937A US06/912,941 US91294186A US4752937A US 4752937 A US4752937 A US 4752937A US 91294186 A US91294186 A US 91294186A US 4752937 A US4752937 A US 4752937A
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United States
Prior art keywords
gas laser
cooling
gas
laser
electrodes
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US06/912,941
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English (en)
Inventor
Wolfram Gorisch
Rolf Malkmus
Rainer Nitsche
Walter Skrlac
Dieter Wendt
Walter Wohlfart
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
WC HERAEUS A GERMAN CORP GmbH
Thermo Electron LED GmbH
Laserscope Inc
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WC Heraus GmbH and Co KG
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Assigned to W.C. HERAEUS GMBH, A GERMAN CORP. reassignment W.C. HERAEUS GMBH, A GERMAN CORP. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: WENDT, DIETER, WOHLFART, WALTER, GORISCH, WOLFRAM, MALKMUS, ROLF, NITSCHE, RAINER, SKRLAC, WALTER
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Publication of US4752937A publication Critical patent/US4752937A/en
Assigned to HERAEUS INSTRUMENTS GMBH reassignment HERAEUS INSTRUMENTS GMBH ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: W.C. HERAEUS GMBH
Assigned to LASERSCOPE reassignment LASERSCOPE ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: W.C. HERAEUS GMBH
Assigned to SILICON VALLEY BANK reassignment SILICON VALLEY BANK SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: LASERSCOPE
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/02—Constructional details
    • H01S3/04—Arrangements for thermal management
    • H01S3/041—Arrangements for thermal management for gas lasers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/02—Constructional details
    • H01S3/03—Constructional details of gas laser discharge tubes
    • H01S3/0305—Selection of materials for the tube or the coatings thereon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/097—Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser
    • H01S3/0975—Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser using inductive or capacitive excitation

Definitions

  • the present invention relates to a gas laser and a proces of making it.
  • a known gas laser has a coolable inner electrode for connection to a radio-frequency power source and a coolable outer electrode that is coaxial with and radially spaced from the inner electrode.
  • An excitation in the space between the electrodes contains the gas to be lasingly excited.
  • Each side of the excitation space in the axial direction is bounded by a mirror.
  • a gas laser of this type is known from published German patent application DOS No. 33 39 574. Such lasers have proved themselves in actual use.
  • the inner electrode is surrounded in a spaced relationship by a sheathing tube of copper, the inner electrode and the sheathing tube being connected to a radio-frequency power source.
  • a liquid containing fluorocarbon compounds such as the product marketed by Kalie Chemie AG under the trade name Flutec PP3, flows through the space between them for cooling purposes. This liquid coolant is distinguished by low losses for radio-frequency fields.
  • outer electrode consists of a metal tube that is highly-conductive electrically and grounded. Its inner electrode is in the form of a sheathing tube spacedly jacketed in another sheathing tube made of a dielectric material, a liquid coolant flowing through the space between these two sheathing tubes for cooling the inner electrode.
  • An object of the invention is to improve a laser of this type for excitation at higher power with retention of homogeneous discharge, slower lasing-gas decomposition, and use of any desired, appropriate, fluid, preferably-liquid coolant regardless of the electrical conditions.
  • this and other objects are achieved by radially bounding an excitation space between inner and outer, coaxial, radially-spaced fluid-cooled electrodes of a gas laser with two, tubular dielectric bodies which are coaxial with and radially spaced from each other. These tubular dielectric bodies completely shield the excitation space and a lasingly-excitable gas to be contained therein physically from the inner and outer electrodes.
  • decomposition of the gas and gettering on the surfaces of the preferably-ceramic, tubular dielectric bodies are reduced by comparison with a laser arrangement in which the gas is in direct contact with the surface of at least one of the electrodes. Consequently, consumption of the gas is also reduced in both closed-loop and continuous-flow operation of the laser.
  • the laser of the invention is further distinguished by more homogeneous laser excitation, which also contributes to improved efficiency.
  • the generally radio-frequency excitation power can be increased. This can affect the homogeneity of the laser output, but homogeneous output is always desirable at all output powers.
  • microarc or arc discharge from the metal electrode occurs above a certain excitation-power threshold which depends on the dimensions of the laser and other factors. This microarc or arc discharge causes the output power to drop off and, thus, the efficiency of the laser to decrease. It is of advantage, therefore, that the threshold above which these detrimental microarcs or arcs develop is much higher when, instead, the dielectric bodies bound the excitation space for contact with the gas.
  • these may be provided with a cooling coil or cooling liner or jacket.
  • the inner and/or outer electrodes are permanently united with the dielectric body respectively associated therewith, more preferably so that there is no separation between the respectively-united electrodes and dielectric bodies. This can be accomplished, for example, by pressure-applying an appropriatelydimensioned tubular conductor to the inner surface of the dielectric body for the inner electrode or to the outer surface of the dielectric body for the outer electrode. Perforated or latticed tubular conductors are particularly suitable for this.
  • a particularly good bond between the inner and/or outer conductor and the respective dielectric bodies is obtained when the inner and/or outer conductor is formed by a baked-on metallizing paste.
  • the metallizing paste is applied to the surface of the ceramic body by brush, for example, or sprayed onto it, and then baked on.
  • Well suited for the purpose is a silver or copper paste, and particularly a molybdenum/manganese paste.
  • tubular dielectric bodies for example, ceramic bodies
  • whose wall comprises hollow spaces (channels) which are filled with a metal that forms the electrodes.
  • the metal is conductively connected to one terminal of the power source, so that the electrode is fully protected against corrosion.
  • the inner conductor is preferably water-cooled, which is feasible since the cooled zone and the cooling medium are not situated in the radio-frequency field.
  • a liquid coolant distinguished by low losses for radio-frequency fields is not required.
  • the laser then is particularly well suited for medical applications since liquid coolants which are innocuous from the health standpoint, such as water, can.then be used.
  • the dielectric bodies used are preferably alumina-ceramic parts.
  • FIG. 1 shows a gas laser in accordance with the invention which is operated on a continuous gas-flow basis
  • FIG. 2 shows an embodiment representing a modification of that of FIG. 1 with recirculated gas flow and a modified cooling system for the inner electrode.
  • the gas laser comprises an inner ceramic tube 1 and, disposed coaxially therewith, an outer ceramic tube 2. Between the inner ceramic tube 1 and the outer ceramic tube 2, an annular excitation space 3 is formed which contains the gas to be excited.
  • the gas is fed in through an inlet pipe connection 4 at one end and discharged through an outlet pipe connection 5 at the other end.
  • the excitation space is bounded by laser mirrors 6 and 7, respectively.
  • a tubular inner conductor 8 of copper, for example, is inserted in the inner ceramic tube.
  • the outer conductor 9 is likewise a tubular body. Both the inner conductor 8 and the outer conductor 9 may be perforated or latticed.
  • the inner conductor 8 and the outer conductor 9 are applied to the ceramic bodies 1 and 2, respectively, by pressure to unite them without any gaps between them.
  • a cooling medium is introduced through a coolant feed tube 10, which is inserted into the inner ceramic tube 1 or the tubular inner conductor 8, respectively, and discharged through an annular discharge channel 11, into which the coolant enters at the end of the coolant feed tube 10, and from which it exits through a coolant outlet pipe connection 12 disposed in proximity to the coolant inlet pipe connection 13 of the coolant feed tube 10.
  • the inner conductor 8 is connected to a radio-frequency power source, designated 14.
  • the outer conductor 9 is preferably at ground potential.
  • An outer sheath 15 is spaced from the outer ceramic tube 2 and the outer conductor 9.
  • a cooling medium is fed through a coolant inlet pipe connection 17 to the space 16 between the outer sheath 15 and the outer ceramic tube 2 and discharged through a coolant outlet pipe connection 18.
  • the inner ceramic tube 1' extends outwardly through both laser mirrors 6' and 7', in contrast to the embodiment shown in FIG. 1.
  • the coolant feed pipe 10' used with the laser of FIG. 1 is not required.
  • the cooling medium is introduced through a coolant inlet pipe connection 13' at one end of the inner ceramic tube 1' and discharged through a coolant outlet pipe connection 12' at the other end of the inner ceramic tube 1'.
  • this laser is not operated on a continuous gas-flow basis, and the inlet and outlet pipe connections 4 and 5 are not required.
  • FIG. 1 In the embodiment of FIG.
  • the inner conductor 8' and the outer conductor 9' are deposited in the form of a metallizing paste on the inner surface of the inner ceramic tube 1' and on the outer surface of the outer ceramic tube 2',
  • the metallizing paste in this case a molybdenum/manganese paste, was applied with a brush.
  • the metallizing paste so applied to the ceramic tubes was then baked on in an oven at a temperature ranging from 800° to 1600° C. On top of this baked-on coating, a corrosion-protection layer, which in this case consisted of nickel, was then applied.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Optics & Photonics (AREA)
  • Lasers (AREA)
US06/912,941 1985-10-16 1986-09-29 Gas laser and production process therefor Expired - Fee Related US4752937A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19853536770 DE3536770A1 (de) 1985-10-16 1985-10-16 Gaslaser
DE3536770 1985-10-16

Publications (1)

Publication Number Publication Date
US4752937A true US4752937A (en) 1988-06-21

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US06/912,941 Expired - Fee Related US4752937A (en) 1985-10-16 1986-09-29 Gas laser and production process therefor

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US (1) US4752937A (index.php)
DE (1) DE3536770A1 (index.php)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4922504A (en) * 1988-12-23 1990-05-01 Gil Teva Laser apparatus
US5001721A (en) * 1989-06-16 1991-03-19 Lambda Physik Forschungs- Und Entwicklungsgesellschaft Mbh Apparatus for purifying laser gas
US5007064A (en) * 1988-07-20 1991-04-09 British Aerospace Plc Gas laser
US5164952A (en) * 1990-09-26 1992-11-17 Siemens Aktiengesellschaft Electrically pumped gas laser suitable for high input power
US5177760A (en) * 1990-10-05 1993-01-05 Laser Industries Ltd. Gas laser with internal gas reservoir having long regeneration path
US5386434A (en) * 1993-02-12 1995-01-31 Uniphase Corporation Internal mirror shield, and method for protecting the mirrors of an internal gas laser
US5802087A (en) * 1995-01-11 1998-09-01 Miyachi Technos Corporation Laser apparatus
US6473445B1 (en) * 1999-08-05 2002-10-29 Trumpf Lasertechnik Gmbh Gas laser
US6550934B2 (en) * 2000-07-31 2003-04-22 Secretary Of Agency Of Industrial Science And Technology Light emitting device
US6650680B2 (en) * 2000-09-22 2003-11-18 Trumpf Lasertechnik Gmbh Gas laser with cooled coaxial electrode tubes
CN103872573A (zh) * 2014-04-04 2014-06-18 成都微深科技有限公司 一种半回流式高强度二氧化碳激光器
CN112993724A (zh) * 2021-01-22 2021-06-18 郭秀才 一种气体激光器散热装置

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IL81439A (en) * 1987-01-30 1991-08-16 Alumor Lasers Ltd Ultra compact,rf excited gaseous lasers
DE3810604A1 (de) * 1988-03-29 1989-10-19 Deutsche Forsch Luft Raumfahrt Gaslaser
DE3810601A1 (de) * 1988-03-29 1989-10-19 Heraeus Gmbh W C Gaslaser
DE3923277A1 (de) * 1989-07-14 1991-01-24 Fraunhofer Ges Forschung Gasentladungsanordnung
JPH04276671A (ja) * 1991-03-05 1992-10-01 Matsushita Electric Ind Co Ltd ガスレーザー発振装置

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4325006A (en) * 1979-08-01 1982-04-13 Jersey Nuclear-Avco Isotopes, Inc. High pulse repetition rate coaxial flashlamp
US4359777A (en) * 1981-01-22 1982-11-16 The United States Of America As Represented By The Secretary Of The Army High efficiency transversely excited electrodeless gas lasers
US4455658A (en) * 1982-04-20 1984-06-19 Sutter Jr Leroy V Coupling circuit for use with a transversely excited gas laser
US4553242A (en) * 1983-05-07 1985-11-12 W.C. Heraeus Gmbh Gas laser
US4589114A (en) * 1984-06-19 1986-05-13 Sutter Jr Leroy V Optical mode control for a gas laser
US4597086A (en) * 1983-08-09 1986-06-24 Mitsubishi Denki Kabushiki Kaisha Coaxial type laser oscillator for excitation by silent discharge
US4646313A (en) * 1984-09-26 1987-02-24 Siemens Aktiengesellschaft Inert gas ion laser

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2735299C2 (de) * 1977-08-05 1986-08-28 W.C. Heraeus Gmbh, 6450 Hanau Elektrisch angeregter Gaslaser
DE3316778C1 (de) * 1983-05-07 1984-10-18 W.C. Heraeus Gmbh, 6450 Hanau Gaslaser
US4785458A (en) * 1984-02-13 1988-11-15 Mitsubishi Denki Kabushiki Kaisha Gas laser device

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4325006A (en) * 1979-08-01 1982-04-13 Jersey Nuclear-Avco Isotopes, Inc. High pulse repetition rate coaxial flashlamp
US4359777A (en) * 1981-01-22 1982-11-16 The United States Of America As Represented By The Secretary Of The Army High efficiency transversely excited electrodeless gas lasers
US4455658A (en) * 1982-04-20 1984-06-19 Sutter Jr Leroy V Coupling circuit for use with a transversely excited gas laser
US4553242A (en) * 1983-05-07 1985-11-12 W.C. Heraeus Gmbh Gas laser
US4597086A (en) * 1983-08-09 1986-06-24 Mitsubishi Denki Kabushiki Kaisha Coaxial type laser oscillator for excitation by silent discharge
US4589114A (en) * 1984-06-19 1986-05-13 Sutter Jr Leroy V Optical mode control for a gas laser
US4646313A (en) * 1984-09-26 1987-02-24 Siemens Aktiengesellschaft Inert gas ion laser

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5007064A (en) * 1988-07-20 1991-04-09 British Aerospace Plc Gas laser
US4922504A (en) * 1988-12-23 1990-05-01 Gil Teva Laser apparatus
US5001721A (en) * 1989-06-16 1991-03-19 Lambda Physik Forschungs- Und Entwicklungsgesellschaft Mbh Apparatus for purifying laser gas
US5164952A (en) * 1990-09-26 1992-11-17 Siemens Aktiengesellschaft Electrically pumped gas laser suitable for high input power
US5177760A (en) * 1990-10-05 1993-01-05 Laser Industries Ltd. Gas laser with internal gas reservoir having long regeneration path
US5386434A (en) * 1993-02-12 1995-01-31 Uniphase Corporation Internal mirror shield, and method for protecting the mirrors of an internal gas laser
US5802087A (en) * 1995-01-11 1998-09-01 Miyachi Technos Corporation Laser apparatus
US6473445B1 (en) * 1999-08-05 2002-10-29 Trumpf Lasertechnik Gmbh Gas laser
US6550934B2 (en) * 2000-07-31 2003-04-22 Secretary Of Agency Of Industrial Science And Technology Light emitting device
US6650680B2 (en) * 2000-09-22 2003-11-18 Trumpf Lasertechnik Gmbh Gas laser with cooled coaxial electrode tubes
CN103872573A (zh) * 2014-04-04 2014-06-18 成都微深科技有限公司 一种半回流式高强度二氧化碳激光器
CN112993724A (zh) * 2021-01-22 2021-06-18 郭秀才 一种气体激光器散热装置

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Publication number Publication date
DE3536770A1 (de) 1987-04-16
DE3536770C2 (index.php) 1989-12-07

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